Engine muffler



Dec. '24, 1929. w. T. SCARRITT ENGINE MUFFLER Filed Feb. 17, 1928 IIIIIIIIIIII INVENTOR mnZkmp Z'Jca rriZZ ATTORNEY WKTNESSES Patented Dec. 24, 1929 UNITED STATES PATENT OFFICE WINTHROP T. SCARRITT, F UTICA, NEW YORK, ASSIGNOR TO, PRATT CHUCK COM- IPANY, 0F UTIGA, NEW YORK, A CORPORATION OF NEW YORK ENGINE MUFFLER Application filed February 17, 1928. Serial-No. 255,111,.

The present invention is concerned with a mufiier for internal combustion engines.

- The muffler is of the type commonly used in connection'with the engine exhaust pipe, and

includesa series of compartments through which sound waves and exhaust gases must pass to reach the outer air. These various compartments communicating with each other onlythrough restricted orifices, present a succession of baflie walls and sound wave interrupting surfaces which cause the sound waves to be completely broken up and subdued by the time they escape from the muf fler.

A conventional method of construction heretofore used in connection with this type of mufiler includes a plurality of cup-shaped mufiier sections partially nested one within theother, and connected to form along cy lindrical muffler by the use of tie bolts passing through all of the sections. The b .ttoms of these partially nested sections constitute the bafile walls-and are provided with openings therein which afford communication between the adjacent mufiler chambers.

The cup shaped sections commonly .employed are particularly desirable in that sections which have been burned out or other-' wise injured may be readily removed and re- 0 placed at slight cost. The useof this type of mufller however, has always presented one major difliculty which rendered proper assembly of the, cup shaped sections difficult. Eachof the sections has been formed necessarily of rather thin gauge stock punched and rolled to define acup having openings in its bottom and a narrow external shoulder near its bottom, defining a reduced portion over which the mouth of an adjacent cup fits. The width' of this shoulder in accordance with conventional practice is identical with the thickness of the adjacent cup. which abuts it. Consequently, when tie bolts have been passed through an aligned series of nested cups and tightened, the mouth of one cup fre- -fully set forth and pointed out in the claims.

quently spreads, and slipping over the shoulder tends to telescope over an adjacent cup. Obviously, such telescoping would cause undesirably deep nesting of two cup sections and would also destroy the positive abutment between adjacent sections. 7

In accordance with the present invention, I

have overcome this difficulty by the use of, v

cups having shoulders of materially greater width than the thickness of the cup edges WlllCh rest upon them. Thus, the flaring or belling and consequent telescoping action is.

eliminated, and the adjacent partially nested cup sections maybe clamped tightly together by the tie bolts.

With the above noted and other objects in view, the invention consists in certan novel features of construction, and combinations and arrangements of parts, as will be more The invention may be more fully understood from the following description in connection with the accompanying drawings, wherein Fig. 1 is a view partly in side'elevation and partly in longitudinal section through a muffler embodying the present invention. Fig. 2 is a perspective view of one of the cup-shaped mufiler sectiohs. i

Fig. 3 is an enlarged detail sectional view through several adjacent sections.

Fig. 4 is a view similar to Fig. 3, but illustrating a modification.

Fig. 5 is a view similar to Fig. 3, but illu'strating a further modification. A

In Figs. '1 to.3 of the drawings I hav sed 30 the reference numeral 10 to indicate general- 1y each cup shaped section, which'se'ction includes a bottom 11, circular side 'wall'12, and openings 13 in the bottom through which exhaust gases may pass. Each cup shaped section 10 adjacent its bottom 11 is provided with an external shoulder 14 defining a reduced portion 12 of the wall 12, which reduced portion is adapted to conveniently fit within the mouth of an adjacent cup 10.

Shoulder 14 contrary to the conventional practice is of materially greater width than the thickness of the metal used in forming the cups, so that it will form a substantial abutment for the mouth of an adjacent cup, and the series of cups will not tend to telescope one upon the other when the tie bolts 15 are tightened. The shoulder 14:, as shown in Figs. 1 and '3, is of rolled formation as differentiating from an angled shoulder. This formation provides a corrugation in conjunction with the shoulder, thus to provide compensating means for the contraction and expansion of the associate members.

These tie bolts pass through suitable openings 15 (not shown) in the bottoms 11 of all of the cup-shaped sections, and through head plates 16 and 17 at opposite ends of the muffler; these plates carrying the outlet and inlet pipes 18 and 19 through which the gases are conducted. I

With particular reference to Fig. 3, it will be noted that the shoulder 14 is produced by rolling, and is disposed at right angles to the cup wall 12 and the reduced portion 12 of said wall, whereby it defines a flat substantial abutment for the lip of an adjacent cup, and when the cups are partially nested within each other, the shoulders, or rather 30 form the shoulders, define a series of annular the outwardly extending cup portions which ribs 20 which materially assist in strengthening the muffler against transverse bending strains.

In Fig. 4 I have-illustrated a modification in which a shoulder 14: similar to theshoulder 14 is used. This shoulder, however, in: stead of being abruptly formed as by the ribs 20 is formed .by gradually tapering the side walls 12 of the cups-10. In the modification shown in Fig. 5, the cup 10 also includes a gradually tapering wall 12.- Instead of forming simply a shoulder. however, the metal of the cup wall 12 is rolled into a substantially S configuration in cross section defining an actual groove 21 receiving the lip of an adjacent cup section.

With this form of the invention, one side of the S-curve constitutes the groove, and

the other side constitutes a rib 22 serving as a strengthening rib much in the manner of the ribs 20 in Fig. 1.

In all forms of the invention, a substantial shoulder is provided which prevents the cups from telescoping one upon the other ..when the tie bolts 15. are tightened. In other words, the shoulders accurately predetermine the extent to which the cups may be nested one within the other. An extremely rugged construction is had due to the fact that the bolt 15 may be tightened to firmly jam the cups against each other, and due to the fur ther fact that the ribs 20 or 22 serve to strengthen the sectional muflier against transverse strains.

Obviously, various changes and alterations might be made in the general form and arrangement of the parts described without departing from the invention. Hence I do not toms providing communication between the chambers, tie bolts or the like connecting all of said members and holding them in properly nested relationship, each of said cupshaped' members including a rolled external annular shoulder extending beyond the periphery of the bottom of said cup-shaped member and located between its bottom and lip against which the lip of an adjacent cu abuts, the shoulder being of greater widt than the thickness of the cup lip which abuts it, the shoulder presenting an annular reinforcing rib extending laterally beyond the lip of the adjacent cup and providing a compensating means for the expansion and contraction of the members.

2. In an engine muffler, a plurality of generally cup shaped members partially nested one within the other and defining chambers, said members having openings in their bottoms providing communication between the chambers, tie bolts or the like connecting all of said members and holding them in properly nested relationship, each of said cupshaped members including an external annular shoulder between its bottom and lip against which the lip of an adjacent cup abuts, the shoulder being of greater width than the thickness of the cup lip which abuts it and constituting the bottom of an annular groove produced by rolling part of the cup side wall back upon itself.

3. In'an engine mufiler, a plurality of cupshaped members partially nested one within the other and defining chambers, said members having openings in their bottoms "providing communications between the chambers. tie bolts or the like connecting all of said members and holding them in properly nested relationship, each of said cup-shaped members including portions overlapping in spaced relation to provide a receiving groove for the lip of the next adjacent cup-shaped member. k I

4. In an engine muflier, a plurality of cupshaped-m'embers partially nested one within the other and defining chambers, said members having openings in their bottoms pronested relationship, each of said cup-shaped members including a slanting side wall terminating in overlapping portions provided with spaced angularly related walls adapted to form a groove for guiding and receivin the lip of the next adjacent cup-shape member. 7

Si ed at Utica, in the county of Oneida and tate ofNew York, this 15 day of Feloruary, A. D. 1928. p

WINTHROP T. SCARRITT. 

